Three dimensional (3D) video systems garner great interest for enhancing a consumer's experience, whether at the cinema or in the home. These systems use stereoscopic or auto-stereoscopic methods of presentation, including: anaglyph, linear polarization, circular polarization, shutter glasses, and spectral separation.
Most of the 3D displays available in the market today are stereoscopic televisions (TVs), requiring the user to wear shutter 3D glasses in order to experience a 3D effect. Delivery of 3D content to these displays requires carrying two separate views: a left view and a right view. Wide adoption of auto-stereoscopic (glasses-free) displays is in the horizon. These displays provide some amount of motion parallax; the viewer can slightly move his/her head around to view objects from vastly different angles.
Traditional stereoscopic displays provide a single 3D view; however, auto-stereoscopic displays (also called multi-view displays) provide multiple views such as five views, nine views, 28 views, etc., based on the design of the display. When conventional stereoscopic content is provided to auto-stereoscopic displays, the displays extract depth maps and create or render multiple views based on this depth map. As used herein, the term “depth map” denotes an image or other bit-stream that contains information related to the distance of the surfaces of scene objects from a viewpoint. As more fully explained below, a depth map can be readily converted to a disparity map, and in the context of this document the terms depth map and disparity map are the same and inter-changeable.
The depth map information also may be used for tailoring the 3D experience for different displays types with different resolutions and display size (e.g., 1080p displays or 4K displays). There have been a number of studies showing the amount of depth designed for 3D cinema is not suitable for smaller mobile devices and vice-versa. The depth map could be used to re-render the views to alter the perceived depth and to make additional adjustments. As appreciated by the inventors here, improved techniques for delivering depth maps along with the content are desirable for improving the user experience with auto-stereoscopic and stereoscopic displays. It is further appreciated that these improved techniques preferably are backwards compatible with existing single-view (2D) and 3D systems.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. Similarly, issues identified with respect to one or more approaches should not assume to have been recognized in any prior art on the basis of this section, unless otherwise indicated.